1. Field of the Invention
The present invention relates to an image display apparatus including a communication interface for communicating with a rendering apparatus, and to a method for controlling the image display apparatus.
2. Description of the Related Art
Televisions that display the graphics of a menu screen, an electronic program guide (EPG), and the like in addition to video images of a program have been in use. Recent televisions, especially digital televisions (DTVs), have a high resolution display, and are capable of displaying high-definition images. Thus, the quality demanded of the graphics of a menu screen, an electronic program guide, and the like has also increased.
A recording apparatus (for example, a DVD recorder) that renders the graphics of a menu screen, an electronic program guide, and the like; that outputs the rendered graphics to a television; and that causes the graphics to be displayed; is also known. Furthermore, a cellular phone that causes an external display device to render images has also been proposed (see Japanese Patent Laid-Open No. 2004-032104).
In general, an image display apparatus such as a DTV does not have very high graphic rendering ability. Although the rendering ability of an image display apparatus can be improved if a highly functional graphics card such as that provided in a personal computer (PC), a recent game console, or the like is provided, providing such a highly functional graphics card causes disadvantages such as increases in power consumption and cost. Because the main purpose of an image display apparatus such as a DTV is to display images, it is not favorable in a product to increase the graphic rendering ability when an improvement in graphic rendering ability causes such disadvantages.
The image display apparatus itself does not have to have high rendering ability when graphics rendered by an external apparatus are displayed on the image display apparatus, based on a conventional technique such as the one described in Japanese Patent Laid-Open No. 2004-032104. However, in this case, images displayed on the image display apparatus are different in every external apparatus, possibly having a negative impact on user convenience. For example, when an electronic program guide rendered by a recording apparatus is to be displayed on a DTV, the layout, the operation method, and the like of an electronic program guide differ for different recording apparatuses, possibly causing confusion on the part of the user. Also, consistency cannot be maintained between the graphics rendered by the image display apparatus itself and the graphics rendered by the external apparatus. For example, a layout, an operation method, and the like may be different between an electronic program guide rendered by the DTV, and an electronic program guide rendered by the recording apparatus, possibly causing confusion on the user's side.
Having been conceived in light of such circumstances, the present invention provides a technique for outputting an image rendered by an external rendering apparatus while inhibiting a negative impact on the user convenience of an image display apparatus.